A pairing server (313) includes: a first generation unit (317a) which generates a first pairing identifier when the pairing server receives a first request from a receiving terminal (307); a first transmitting unit (316a) which transmits the first pairing identifier to the receiving terminal (307) in response to the first request; a second generation unit (317b) which generates a second pairing identifier when the pairing server receives from a transmitting terminal (301) a second request which includes the first pairing identifier; a second transmitting unit (316b) which transmits the second pairing identifier to the receiving terminal (307) or the transmitting terminal (301) in response to the second request; and a pairing unit (315e) which pairs the receiving terminal (307) and the transmitting terminal (301) when the pairing server receives a third request which includes the first pairing identifier and the second pairing identifier.